1. Field of the Invention
The present invention relates to a radio-frequency module disposed between a radio-frequency integrated circuit (RFIC) which performs signal processing on radio-frequency signals of different multiple frequency bands and an antenna which transmits or receives radio-frequency signals, and also to a communication device including the radio-frequency module.
2. Description of the Related Art
In accordance with a reduced size and a more demanding specification of communication devices such as smartphones, a radio-frequency module, such as a radio-frequency front-end module, used in a communication device is becoming increasingly complicated. For example, the mounting density of components on a radio-frequency module is becoming higher and the circuit configuration of a radio-frequency module is becoming more complicated. It is more desirable that such a radio-frequency module exhibit high performance as the entire module by combining plural filters and plural switch circuits.
As an example of such a radio-frequency module, the following configuration is disclosed. A matching circuit between an external-connecting terminal and a filter unit is inductively or capacitively coupled with an inductor between a ground and a filter unit (for example, see International Publication No. 2015/019980).
In the above-described radio-frequency module of the related art, only a single frequency band is used as a communication band. In such a single communication system in which only a single frequency band is used as a communication band, a leakage of a transmitting signal into a reception path can be prevented by separating input and output signal lines from each other, for example.
Lately, radio-frequency modules which support multiband communication have been provided. In such a radio-frequency module, different multiple frequency bands are used as communication bands, and thus, plural band pass filters for the respective multiple frequency bands and a switch to select the communication band may be provided. In a multiband system, the transmit band of a first communication system and the receive band of a second communication system may overlap each other. Because of this reason, in a multiband system, it is more important that desired transmission characteristics be obtained by securing the isolation between an input side and an output side, compared with a single communication system. In order to satisfy such a demand, a circuit on the input side of the switch and a circuit on the output side thereof are generally disposed separately from each other.
However, as the mounting density of components increases, it is more difficult to separate a circuit on the input side of the switch and a circuit on the output side thereof from each other. This makes it more difficult to obtain desired transmission characteristics.